China National Offshore Oil Corporation (CNOOC), the country's largest offshore oil producer, announced Tuesday that it has successfully appraised the Penglai(PL)9-1 hydrocarbon bearing structure following its discovery in 2010. The appraisal confirmed that PL9-1 is a large oil field.

PL9-1 is located in the Miaoxibei uplift, in the eastern portion of the Bohai Sea, with an average water depth of 25 meters. PL9-1-5, an appraisal well, encountered oil pay zones in buried hills, and has been tested to produce around 700 barrels of oil per day. In terms of scale, PL9-1 is the largest oil field to have been discovered in the Bohai Sea in recent years. CNOOC has also made a successful discovery of the PL15-2 structure, located 8 kilometers south of PL9-1.